Extremely solvent-enhanced absorption and fluorescence spectra of carbazole were investigated by performing a generalized multi-set damped Franck-Condon spectral simulation. Experimental absorption and fluorescence spectra of carbazole in the gas phase were first well reproduced by performing an un-damped Franck-Condon simulation, but a one-set scaling damped Franck-Condon simulation severely underestimated the intensities of the peaks of experimental absorption and fluorescence spectra of carbazole in n-hexane. Then, a multi-set scaling damped Franck-Condon simulation was proposed and carried out for simulating the extremely solvent-enhanced absorbance and fluorescence, and here, the simulated spectra agreed well with the experimental ones. Five (four) representative solvent-enhanced normal modes corresponding to the combination of ring stretching and ring breathing vibrational motions were determined to be responsible for enhanced absorbance (fluorescence) in n-hexane solution. Furthermore, different scalings were applied to the ground and first-excited states, resulting in different enhancement of absorbance and fluorescence, and this analysis revealed atoms in the carbazole interacting with n-hexane solvent molecules and, hence, leading to different normal-mode vibrational vector patterns in the ground and first-excited states, respectively. Basically, the same conclusion was drawn from a simulation with HF-CIS and the three functionals (TD)B3LYP, (TD)B3LYP-35, and (TD)BHandHLYP. The present multi-set scaling damped Franck-Condon simulation scheme was demonstrated to successfully interpret extremely solvent-enhanced absorbance and fluorescence of carbazole in n-hexane-solvent.Markov processes are widely used models for investigating kinetic networks. Here, we collate and present a variety of results pertaining to kinetic network models in a unified framework. The aim is to lay out explicit links between several important quantities commonly studied in the field, including mean first passage times (MFPTs), correlation functions, and the Kemeny constant. We provide new insights into (i) a simple physical interpretation of the Kemeny constant, (ii) a relationship to infer equilibrium distributions and rate matrices from measurements of MFPTs, and (iii) a protocol to reduce the dimensionality of kinetic networks based on specific requirements that the MFPTs in the coarse-grained system should satisfy. We prove that this protocol coincides with the one proposed by Hummer and Szabo [J. Phys. Chem. B 119, 9029 (2014)], and it leads to a variational principle for the Kemeny constant. Finally, we introduce a modification of this protocol, which preserves the Kemeny constant. Our work underpinning the theoretical aspects of kinetic networks will be useful in applications including milestoning and path sampling algorithms in molecular simulations.Ionic polarization and dielectric function play a fundamental role in the optoelectronic properties of hybrid perovskites, currently one of the most studied materials for next generation photovoltaics. The hybrid nature of the crystal, with molecular dipoles that can reorient within the inorganic lattice, gives rise to a complex dielectric response in the bulk material that has been largely studied and debated. Here, we investigate the nature and the relaxation properties of the dielectric polarization of hybrid perovskites at finite temperature by means of classical molecular dynamics. We provide evidence that a simple ionic model of classical interatomic forces is able to explain qualitatively the temperature and frequency dependence of the dielectric constant providing a picture that is fully consistent with experimental data. The constant dielectric function in the low-temperature phase is controlled by ionic displacements, while the temperature-dependent paraelectric behavior of the tetragonal phase is due to reorientation of dipoles that are responsible for the discontinuity at the orthorhombic-to-tetragonal transition. In the frequency domain, the molecular reorientations give rise to a broad band that is located in the 0.1 THz timescale at room temperature and that shifts down to the GHz timescale when cooling the system toward the tetragonal-to-orthorhombic phase transition. The relation between relaxation time and maximum absorption frequency is also clarified.Liquid-phase exfoliation, the use of a sheared liquid to delaminate graphite into few-layer graphene, is a promising technique for the large-scale production of graphene. However, the microscale and nanoscale fluid-structure processes controlling the exfoliation are not fully understood. Here, we perform non-equilibrium molecular dynamics simulations of a defect-free graphite nanoplatelet suspended in a shear flow and measure the critical shear rate γ?c needed for the exfoliation to occur. We compare γ?c for different solvents, including water and N-methyl-pyrrolidone, and nanoplatelets of different lengths. Using a theoretical model based on a balance between the work done by viscous shearing forces and the change in interfacial energies upon layer sliding, we are able to predict the critical shear rates γ?c measured in simulations. We find that an accurate prediction of the exfoliation of short graphite nanoplatelets is possible only if both hydrodynamic slip and the fluid forces on the graphene edges are considered and if an accurate value of the solid-liquid surface energy is used. The commonly used "geometric-mean" approximation for the solid-liquid energy leads to grossly incorrect predictions.We present a numerical study of the wrapping of spherical nanoparticles by tensionless lipid membranes using molecular dynamics simulations of a coarse-grained implicit solvent model. https://www.selleckchem.com/products/ndi-091143.html We found that the degree of wrapping of small nanoparticles increases continuously with the adhesion strength for nanoparticles with diameter less than or about 15 nm. In contrast, the increase in the degree of wrapping becomes discontinuous for larger nanoparticles and exhibits a clear hysteresis when upward and downward annealing scans with respect to adhesion strength are performed. The gap in the degree of wrapping increases with the increase in the diameter of nanoparticles. These results are in qualitative agreement with the mean field prediction that large nanoparticles are either unbound or completely wrapped by tensionless lipid membranes.